Effects of low dose x-ray on development and differentiation of cerebral cortex, 13

ICR mice were irradiated with 25 or 100 R of x-ray at 17 days of pregnancy, and 3H-thymidine was injected immediately after the irradiation. The brain of progenies which were born from irradiated ICR mice was extracted 4 weeks after their birth, and histoautoradiography of the cerebram were made. Distribution of nerve cells labelled strongly with 3H-thymidine was observed, and the construction of cerebral cortex was discussed. Abnormality in parietal region of new cerebral cortex in which nerve cells labelled strongly with 3H-thymidine distributed was not found, but a count of nerve cells distributing tended to decrease according to exposure dose. (Tsunoda, M.)